Automotive manufacturers typically mass produce vehicles in standard configurations, as it is not efficient or economical to produce configurations for which there is limited demand. For example, it may be worth establishing an assembly line for a configuration with a demand of 1,500 units per year, but not for a configuration with a demand of 800 units per year. However, it may be desirable for many automotive fleets to have special features. For example, it may be desirable for garbage trucks to have right-side steering wheels and/or standing driving cabs. Likewise, it may be desirable for auto-haulers to have shorter cabs, such that larger vehicles may be carried over the cab while still allowing 13 ft. 6 in. bridge limits to be met nationally. In such cases, automotive modification companies profitably fill the void, modifying, vehicles to meet the requirements of specific applications.
During the time up until approximately the year 2004, truck modification companies would commonly achieve a lowered cab height by simply lowering the entire cab on the frame so that the cab sits closer to the ground. Emission standards enacted around the year 2004, however, required the addition of exhaust gas recirculation (EGR) systems to trucks. As a result, concern of air flow under the cab prevented extreme lowering of the cab. In 2007, diesel particulate systems were added, which include significant additions to the chassis-mounted muffler systems. These components are typically require air flow around them to function properly. As a result, lowering the cab was no longer a solution to lowering the truck cab height.
Commonly owned U.S. Pat. No. 7,395,591 to Prosser et al. offers an alternative solution for lowering a truck cab height whereby sections of the cab A and B-pillars and back wall are removed. While the Prosser et al. '591 patent provides a standardized process for reducing the cab height of a truck, it is desirable to have a roof assembly specifically adapted for this purpose. It would be particularly advantageous if such an assembly provided the truck with an original equipment manufacturer look.
Furthermore, a critical element in the transporting of automobiles via heavy trucks is the quantity of vehicles that may be carried per truck load. A particular limiting factor is the length of the ears being carried with respect to the “Bumper to Back of Cab” distance. It would be particularly advantageous to provide a truck cab modification that increases the load capacity of the truck by addressing this issue.